In situ fixing of clips of this type is secured by means of U-shaped rivets or staples of metal wire, the two arms of the rivets or staples being pressed through apertures in a first bowed part of such a clip and then through the conveyor belt and then being led out through other apertures in the opposite bowed part of the clip. The staples are driven in by means of a drift which is applied consecutively to the top of each staple, the clips being supported during this step on a support member effective as an anvil. The support member is formed with grooves for receiving the staple tines in order to bend them round and press them onto the outside surface of the corresponding bowed part of the clips.
To ensure that the clips thus disposed are securely fixed in situ, drifting or machines have to be used which can provide very high pressures to produce the beaded connection between the staple tines and the clips. This calls for the use of relatively complex and costly machines.